In a typical electric power steering (EPS) system, a hand wheel is connected to a shaft, which comprises an upper shaft and a lower shaft connected by a torsion bar. The upper shaft connects to the hand wheel and the lower shaft connects to an intermediate shaft that ultimately connects to the rack and pinion gear of a vehicle. When the hand wheel is turned, the upper shaft rotates and a torque sensor measures the angular displacement of the torsion bar. The torque sensor is typically located at the interface between the upper and the lower shaft, which is also the location of the torsion bar. The type of torque sensor typically used has been a contacting type, which requires use of a torsion bar to measure the amount of twist on the torsion bar. The torque sensor sends a signal to the controller, which then sends a signal to the motor to begin operating. The motor powers a gear mechanism, which provides assistance in turning the lower shaft and ultimately the road wheels.
An electric power steering system for a vehicle comprising a hand wheel in operable communication with a shaft, a motor in mechanical communication with the shaft, and a non-compliant torque sensor located at the shaft between about a midpoint along the shaft and an upper end of the shaft.